Ask HN: What did you find out or explore today?

Software, AI & Developer Tooling

• Many explored small technical tricks: tel: URIs in HTTP redirects, strings and Ghidra for binary inspection, curl timing flags, mDNS with .local hostnames, systemctl --host, git worktree/rerere, PHP’s natural-language date modifiers, and DuckDB reading JSON and Kafka dumps.
• Several built or refined tools: a sheet‑cutting optimizer and the gap between NP‑hard “optimal” layouts and human‑legible diagrams; a local Streamlit LLM frontend over Databricks’ models; an RS485/Modbus‑controlled home battery driven by Home Assistant; adversarial‑example-based CAPTCHAs; a tiny‑LLM fine‑tuning pipeline; a personal AI CLI test harness.
• There’s interest in alternative stacks: Swift/AppKit with make instead of Xcode, experiments with Nim and Odin for SDL3 games (with AV false‑positive worries), NixOS containers where non‑root can install packages, and a homegrown React alternative whose complexity is surprising.
• One data engineer describes a “fourth way” to manage data‑lake schema evolution via parallel arrays/vertical partitioning. Others are skeptical, comparing it to simple array zipping and pointing to prior art (LanceDB, vector DBs).

Hardware, Systems & Physical Tech

• Robotics and electronics work exposed confusing cable “standards” (USB‑C power vs one‑way data, impossible‑to‑find M8 male‑male Modbus cables) and the durability of old protocols like RS485/Modbus.
• People dug into RF and optics: superheterodyne receivers, smart/evolved antennas, and how microscope objectives implement a physical Fourier transform where filters can be placed optically.
• Other practical topics: oiling zerks on machine tools, surströmming as a regulated dangerous good, non‑hardening adhesives, Bluetooth antenna debugging, Raspberry Pi Pico vs old Arduinos.

Life, Hobbies & Personal Discoveries

• A detailed, affectionate account of a conure laying an egg sparks a long ethical thread on keeping birds: some see captivity as cruel denial of flight; others argue for safety, longevity, and analogies to human “self‑imprisonment” indoors. Several note the role of resources and agency.
• Many share hobbies: collecting ancient coins (cheap if not pristine), learning domain‑driven design, building a custom 8‑ball trackball, practicing Freddie King guitar licks, filming skateboarding to correct form, exploring CRT/analog TV timing quirks and PAL/NTSC speed differences.
• Food and culture threads: naturally aged miso vs industrial miso, Costa Rican “Rice and Beans” recipe attempts, kefir and gut microbiome, Santa Muerte devotion in Mexico, light‑pollution‑free stargazing, miso/tea fermentation parallels.

Health, Work & Philosophy

• Indoor CO₂ monitoring with DIY or commercial sensors reveals surprisingly high levels (often ~1500 ppm) in bedrooms and home offices; mitigation attempts include plants, window opening, HVAC fan control, and interest in engineered plants.
• Several explore Stoicism and Seneca, worrying about over‑consumption of commentary vs going to primary texts, and about acting on philosophy rather than just reading it.
• Job‑market frustration appears: truthful SWE résumés getting no traction while embellished ones succeed; others suggest peer résumé review and note companies chasing “Cinderella” hires.
• Misc personal notes: eye strain from constant saccades and experiments with RSVP readers; running and cold showers improving focus; appreciating mains water after a 5‑day outage; moving‑house and mold headaches; discovering “survival” conversational Spanish in real life.